Acoustical units and installed assemblies thereof



y 1960 M. MACCAFERRI 2,

ACOUSTICAL mms AND INSTALLED ASSEMBLIES THEREOF Filed May 15, 1956 5Sheets-Sheet l L A A k v a I5 u N I I4 3 ELL-5-5.

4L I K l MC INVENITOR:

5) 9 M. MACCAFERRI 2,935,152

ACOUSTICAL UNITS AND INSTALLED ASSEMBLIES THEREOF Filed May 15, 1956 5Sheets-Sheet 2 A co ATTORNEYQ y 1960 M. MACCAFERRI 2,935,152

ACOUSTICAL UNITS AND INSTALLED ASSEMBLIES THEREOF Filed May 15. 1956 5Sheets-Sheet 3 y 3, 1960 M. MACCAFERRI 2,935,152

ACOUSTICAL nuns AND INSTALLED ASSEMBLIES THEREOF FiledMay 15, 19565Sheets-Sheetf5 P I6 60 s 54 54 53 I: u :1 n un' w m nn m n unmnnnununnnINVENT OR 3 P k 4m:

ATTORNEYS ACOUSTICAL UNITS AND INSTALLED ASSEMBLIES THEREQE.

Mario Maccaferri, Rye, N31. Application May 15, 1956, Serial No. 585,12)

11 Claims. (Cl. Isl-33) Mypresent invention relates land-is directed toacoustical units and installed assemblies thereof providing acoustical,sound absorbing and deadening surfacesjfor the acoustical treatment ofvarious structures, and the nature andobjectsof the invention willbereadily recognized and understood by those skilled in the artsto whichthe invention relates in the light of the following ex-,

planations and detailed descriptions -'of the accompanying drawingsillustrating what I now consider to be preferredforms of such acousticalunits and preferred installed assemblies thereof embodying my invention,from among various other forms, designs, arrangements, constructions andmechanical and acoustical expressions of which the invention iscapablewithin the broad spirit and scope, thereof as defined in theclaims hereto appended.

Acoustical structures installed for the purpose of absorbinganddeadeningsound waves are mainly used on or as anenclosing wall orwalls of a space to be soundproofed thereby, such as a room or otherenclosed space. As now generally installed and used, such an acousticalstructure usually has the surface ofthe exposed, soundwave receiving.face area thereof parallel with the su-rface of the structure which itcovers or-parallel with the plane of the engaged seating surfaces of themounting for the acoustical structure.- And generally the exposed, soundwave receiving face surface ofthe acoustical structure is also parallelwith the surface opposite it in a space enclosing wall structure. Forexample, ifthe acoustical structure provides t-he ceiling of a, room, itis generally installed with its exposed face surfacepa-rallelwith thesurface of the floor of the room, or, if: it is installed on one of theopposite wall structures, its exposed face surface will be parallel withthe face surface of the opposite wall structure. Where, as is generally,the case, the acoustical structure is formed and installed as anassembly of acoustical units, such as acoustical tiles, then these unitsare conventionally assembled and installed with their exposed face areasparallel and in the same plane with such plane being usually parallelwith the plane of the surface of the opposingwall of a spaceenclosingwall structure. However, it has been determined thatvthe acousticalefficiency and resulting sounda-bsorption andsound-deadening possiblewith such acoustical structures can be substantially increased if theexposed, sound wave receiving face surface of the structure is in aplane that is non-parallel with or at an angle to the opposite exposedface surface of an opposite wall of a space-enclosing wall structure.

One of the primary objects and an important feature of my invention isto increase the acoustical efiiciency of a sound-absorbing and deadeningstructure by providing the exposed, sound-wave receiving surfacethereofformed with sections or portions of said surfacetilted orinclined at angles relative to the general plane of the surface coveredby or the mounting system for such acoustical structure.

A further object is to provide such an acoustical structure formed of aninstalled assembly of acoustical units,

2 a such as acoustical tiles, in which the assembled tiles mak ing upthe acoustical structure have their exposed face surfaces inclined ortilted at angles relative to and nonparallel with the' general plane of"the surface covered by such assembly of acoustical tiles or to thegeneral plane of a structure on whichsuch assembly is mounted;

A further objectis to provide an acountical unit inwhich the facesurface of the unit is inclined or tilted from and relative to thegeneral plane of thesurface or structure onto orover which suchacoustical unit is mounted in installed position thereof. a

-A further objectis to provide an acoustical unit in the form of anacoustical tile, in which the exposed. sound-wave receiving face surfaceof the tile is inclined. or tilted relative to the general plane of thebase or mounting of the tile'in a direction diagonally across the tilefromone location to a diagonally opposite location thereon.

More specifically, my present invention is directed to and concernsacoustical units or ,so-called acoustical tiles formed of plasticmaterial, and particularly to such plastic acoustical tilesof the broadtypes disclosed and exempli-- fied in my pending US. patent applicationsSerial No. 283,707, filed April 22, 1952, for Acoustic Tiles, now

Patent No. 2,755,882, and Serial No. 379,918, filed September 14, 1953,for Acoustical Tile, However, while certain of the features of theinvention may specifically find primary utility in these so-calledplastic acoustic .tiles, such features'a-re not limited to use withplastic acoustic tiles but are adaped and intended for use gen-' erallyin acoustical tiles formed of'various other materials where theadvantages of such features of the iiivention may be'obtained from suchuse. One of the features of the invention of particular utility in theplastic forms of acoustical tiles has asan object the provision of adesign and construction by which such tiles are adapted to mounting andinstallation on standard tile mounting and'suspension systems generallyavailable on the market and in widespread use for mounting tileassemblies, thus avoiding the necessity of the expense and inconvenienceof designing and providing special mounting and installation systemsintended spe-icifically for and generally usable only with such plasticacoustical tiles. is j A further object is to provide a design andconstruction of acoustical tile by which the tile would be adapted foreither mounting and installation on one of the standard acoustical tilemounting suspension systems now available on the market, or for mountingby cementing directly into installed position onto and against a surfacewhich is to be covered and acoustically treated without using anymounting and installation system for direct attachment thereto of thetiles in suspended positions thereon.

Another object is toprovide adesign' and construction of acoustical tilemade of plastic material and of. the types having rearwardlyextendingedge walls or flanges therearound, in which provision is made forexpansion and contraction of the assembled abutting tiles in aninstallation thereof so that the possibility of tile buckling orbreakage by tile expansion and contraction is elimi nated or materiallyreduced and the maintenance of the tiles in their desired installed andassembled positions against displacement or dislodgment is insured.

"A further object is to provide a design and construd tion of each tilefor interlocking with adjacent abutting tiles in an installed assemblyof such tiles so that a system of interlocking is provided for theassembled tiles which materially aids in the precise mounting andassembly of the tiles into the desired installed positions relative toeach other and which system further functions to main- 2,935,152Patented May 3, 196i) tain the tiles in their assembled positions as aninterlocked composite structure.

Another object is to provide a self-contained acoustical unit adaptedfor storage, handling and installation as a unit, which is comprised ofa plastic, pan type acoustical tile with a sound-absorbing mat or padover and against and covering the rear side of the tile in positionsecured on the tile against displacement by discs or plates which alsoprovide cement or mastic receiving surfaces ontheir rear sides by whichthe tile unit can be cemented directly onto a surface in the desiredinstalled position without the necessity of applying cement either onsuch surface or to the sound absorbing pad or mat component of the tileunit.

A further object is to provide such a tile unit in which asound-absorbing pad or mat may be used having substantial portionsthereof of greater depth or thickness than the remaining portions of themat so that the range of sound-wave frequencies which will beeffectively absorbed and dampened by the mat and the tile unit will besubstantially increased with resulting increased acoustical efficiencyof the unit.

A further object is to provide an improved design and construction ofpad retaining and cement receiving discs or plates for such a tile unitwhich will increase the rigidity of the discs or plates on a tile unitand also increase the cementing efiiciency of the cement receivingsurfaces thereof while preventing or substantially reducing thepossibility of cement bleeding or seeping therefrom to the face of thetile unit.

Another object is to provide a plastic acoustical wall tile havingrearwardly extending edge walls or flanges therearound with the adjacentends of adjacent flanges separated to provide for independentdisplacement of adjacent flanges under conditions of expansion andcontraction of a tile occasioned by varying temperatures to which a tileis subjected, so as to thereby eliminate or reduce the possibility ofbuckling or breakage of adjacent tiles in an assembly thereof.

A further object is to provide such an acoustical tile with a cornerconstruction at such separated edge flange ends that will give the tileincreased strength and rigidity and cause the tile to resist unduebending, twisting and warping thereof in handling and installation, aswell as to resist the various forces to which such a tile is subjectedin an installed assembly thereof.

Another object is to provide acoustical units, such as tiles, eachhaving the exposed sound Wave receiving face thereof tilted or inclinedas a planar surface thereacross, adapted for assembly in variousrelative arrangements thereof to provide acoustical structures havingdifferent surface appearances and visual effects at the option of theinstaller.

And further objects are to provide a design and construction of plasticacoustical tile and tile unit formed thereof for carrying out theforegoing objects and features without substantially increasing theWeight of the tile or the cost of production thereof while improving theacoustical efficiency and the appearance of the tiles in variousinstalled assemblies thereof.

With the foregoing objects, features and results as well as certainothers in view, which others will be readily apparent from the followingdetailed description and explanation, my invention consists in certainnovel features in design and construction of parts and components and incombinations and sub-combinations thereof, all as will be more fullyreferred to and specified hereinafter.

Referring to the accompanying drawings in which.

similar reference characters refer to corresponding parts and elementsthroughout the several figures thereof:

Fig. 1 is a generally schematic view in face plan illustrating onepossible assembly and relationship of tilt or inclined face acousticaltile units of my invention in a ceiling installation thereof.

Fig. 2 is a schematic view in face plan of another a '4 assembledrelationship of acoustic tile units of'the in-- vention in a ceilinginstallaiton thereof.

Fig. 3 is a schematic view in face plan of still another relativearrangement of acoustical tile units of the inven-" tion in a ceilinginstallation thereof.

Fig. 4 is a view in edge elevation of adjacent abutting tiles of theinstallation of Fig. 1, taken as from the line 4-4 of Fig. 1.

Fig. 5 is a view similar to Fig. 4 but taken as from the line 55 of Fig.l.

fig. 6 is a view similar to Figs. 4 and 5 but taken as from the line 6-6of Fig. 1.

Fig. 7 is a bottom plan view of a tile unit of the invention without thesound wave absorbing mat or pad and the pad retaining and cementreceiving discs therefor.-

ig. 8 is a transverse sectional view taken as on the line 8-8 of Fig. 7,the tile edge flanges being indicated as sprung or flexed slightlyoutwardly to show the move-* ment thereof independently of the adjacentflanges.

Fig. 9 is a transverse sectional view, similar to Fig. 8 but taken as onthe line 9--9 of Fig. 7. I

Fig. 10 is a bottom or rear side view in plan of the compositeacoustical tile unit of the invention showing the sound wave absorbingpad retaining and mastic receiving discs in assembled positions makingup the selfcontained unit.

Fig. 11 is a transverse sectional view through the acoustical tile unitof Fig. 10 taken as on the line 11-11 of Fig. 10.

Fig. 12 is a rear or underside plan view of one of the pad retaining andmastic receiving disc units of the tile unit of Fig. 10. v

Fig. 13 is a more or less diagrammatic view in transverse sectionthrough abutting edge flanges of adjacent tiles in an assembly thereofshowing the interlocking of the tiles.

Fig. 14 is a view more or less schematic in edge elevation showing apair of connected tile units of the invention in installed position on asuspension system.

Fig. 15 is a detail setcional view through one of the mounting posts andthrough a portion of the tile body showing the manner of attaching thetilein a suspension installation thereof on a suspension system.

Fig. 16 is a fragmentary plan view, of adjacent corners of the pair ofjoined tiles of Fig. 14 showing one of the connecting plates by whichthe tiles are rigidly connected together.

The broad feature of my present invention by which I I provide anacoustical unit, such as an acoustical tile,

with its face tilted or inclined so that when installed the face surfaceof the tile unit will be out of parallelism with the plane of thesurface on which the tile unit is mounted or with the plane of themounting of the tile at the rear or underside thereof, is illustratedand disclosed herein as embodied in tiles and tile units of the plasticmaterial types, such as exemplified in my above referred to pending US.patent applications Serial Nos. 283,707, now Patent No. 2,755,882, and379,918. The embodiment of this tilted face feature of my invention insuch types of plastic acoustical tiles and tile units is purely by wayof example and is not intended as a limitation of this tilted facefeature of the invention to either tiles of plastic material or of thetypes and the specific designs and constructions of the examplesillustrated and disclosed herein. This tilted face surface feature ofthe invention is adapted to embodiment in acoustical tile units oracoustical structures generally formed of any material or materialsother than plastic and to acoustical tiles and acoustical structuresother than the specific designs and constructions herein disclosed, andsuch general adaptability and use is specifically recognized andincluded within the scope of the invention as will be apparent to thoseskilled in this art from the disclosures hereof based on the selectedembodiment examples hereinafter described and explained.

The acoustical tileunit embodying the various features of my inventionwhich I have selected for purposes of Y which will be hereinafterusually referred to as a tile or tile component, and which in thisexample is formed as an injection molded structure of polystyreneplastic. The tile component T is in and of itself an efiicicnt acoustictile when used alone, as will be referred to and described hereinafter.In this specific instance the plastic tile component T. of the unit Uissquare in plan form and may be considered to be or" 12" x 12" in'plandimensions.

This tile component T is itself formed as an integral structureconsisting essentially of a relatively thin, platelike plastic bodyhaving therearound the rearwardly extending edge walls or flanges 11defining and enclosing a space or cavity at the rear side of the tilebody 10. The tile body 10 provides a rear side surface '12 and anexposed sound wave receiving front face forming, generally planarsurface 14. The tile body 10 is provided with a multiplicity ofrelatively closely spaced perforations or sound wave receiving holestherethrough over substantially the entire area thereof, with theseholes 15 extending completely through the body 10 and'discharging at therear side thereof within the cavity enclosed by the edge Walls orflanges 11. i

The tile unit U includes amat or pad P formed of any suitable soundabsorbing or deadening material, such, for example, as glass fibre,secured in positionon and covering the rear side of the tile body Twithin the cavity defined and enclosed by the edge flanges 11. This padP has thicknesses when uncompressed of substantially the depths of theportions of the rearwardly extending edge Walls of flanges 11 extendingtherealong and adjacent thereto, so that in mounted position the rearsurface of the pad lies substantially within and preferably does notextend outwardly substantially beyond the plane of the rear edges of theedge flanges 11. This mat or pad P can, if desired, with certainacoustical units of the invention be secured and retained in position atthe rear side of the tile body 10 by cementing the pad to the rearsurface 12 of the tile body.

In accordance with one of the features of my invention the pad P isformed of different thicknesses throughout the plan dimension thereof toincrease its acoustical efiiciency, as will be described more in detailhereinafter.

However, in accordance with one of the features of my invention thesound absorbing material pad P is secured and retained in its mountedand assembled position in the tile unit U by retaining plates or discstructures C which are rigidly secured to the tile body 10 in positionsthereon spaced rearwardly from the rear surface 12 of the body andextending over the pad P. These retaining disc or plate structures Cpresent at the rear exposed sides thereof the flat, planar surfaceswhich are positioned in this specific example to lie substantiallywithin the plane of the rear edges of the edge walls 11 of the tile T.The planar rear surfaces .30 of the retaining disc structures C areprovided in accordance with the teaching of my invention to form andfunction as cement or mastic receiving surfaces. Thus in thoseinstallations of acoustical tile units where it is necessary or desiredto cement the units directly onto a surface to be acoustically treated,cement may be applied to the rear surfaces 30 of the structures C andthe tile unit then pressed into installed position directly onto thesurface to be treated to engage the cement on structures Cinto adherencewith the surface and thereby secure the tile unit in its installedposition thereof. In this manner the necessity for coating the surfaceson which the acoustical tile units are to be mounted with cement iseliminated and further the application of any cement onto thesound-absorbing material pad? of the unit is avoided.

T of the tile T is planar and extends completely across the r As anexemplification of that feature of my invention by which the acousticalefiiciency of an acoustical tile or tile unit is substantially increasedthrough tilting or inclining the exposed, soundwave receiving facethereof, I have in the acoustical tile unit U of the example hereofinclined or tilted the planar face 14 thereof diagonally across the tileT from one corner to the diagonally opposite corner thereof; The tiltedor inclined face 14 tile as a fiat planar surface in a single plane fromits highest point at one corner of the. tile to the intermediate heightopposite corners and on across the tile to the diagonally opposite lowcorner thereof. In this instance the rear edges 16 of the edge walls 11of the tile T lie in a single plane and it is theflat planar, relativelythin body it? which is bodily tilted or inclined in its entirety acrossthe edge walls 11 that gives and provides the tilt or inclination of thefront, sound wave receiving face 14 across the tile unit. With thisdesign and construction in a tile of generally rectangular plan shape,such as the square tile T of this example, the structure provides fourcorners so that with the body 19 tilted and inclined across the edgewalls 11 there results a high corner '1 with a low corner 3 diagonallyacross the tilefrom the high corner and with the diagonally oppositeintermediate height corners 2 and 4. With the rear edges 16 ofthe edgewalls 11 positioned in a single plane passing therethrough and with thetile body 10 tilted or inclined there.

across from the high corner 1 to the low corner 3, it results that thesection 1B of the edge Wall 11 between the high corner 1 and theintermediate height corner 2 progressively decreases in depth to thelatter corner; the section 2B of the edge wall 11 decreasesprogressively in depth from the intermediate corner 2 to the low corner3; the section 4E of the edge wall 11 opposite or parallel with section25, progressively decreases in depth from the high corner 1 to theintermediate height corner 4; and the section SE of the edge wall 11progressively decreases in depth from the intermediate height corner 4to the low corner 3. With the example tile T having the body 10 and itsface surface 14 tilted or inclined in a single 7 plane diagonallythereacross from the high corner 1 to the low corner 3, the heights ofthe diagonally opposite intermediate corners 2 and 4 from the planepassing through the rear edges of the edge walls 11 will be the same andthe sections 1E and 4B of the edge walls 11 extending between the highcorner 1 and the intermediate corners 2 and 4, respectively, will bedimensionally identical, while the sections 2E and 3B of the edge walls11 which extend between the diagonally opposite intermediate heightcorners 2 and 4 and the low corner 3 will be dimensionally identical.

While in the acoustical tile T of the selected example hereof, therelatively thin tile body It is bodily pitched or tilted diagonallyacross the tile on the edge walls 11,

it is to be understood that if desired or found expedient in thoseacoustical tiles having relatively thicker bodies, the tilt orinclination of the exposed, sound wave receiving front face surface ofthe tile body may be formed as tilted or inclined relative to the rear.side of the tile body and without bodily tilting or inclining the bodyof the tile in its entirety, or by so tilting the tile body but I with areduced angle of tilt. Such formations of an acoustical tile to providethe tilt or inclination to the face thereof in installed position arecontemplated and considered by my present invention in its broad aspectsas the structural and acoustical equivalents of the design andconstruction of the example tile unit hereof.

Each of the sections 1E, 2E, 3E and 4B of the side edge flange or wall11 of the tile T is of the same design and construction and is comprisedby an edge flange 20 which is integral with and extends .rearwardly fromthe body 10 along a side edge thereof. Each flange 2d of the edge flangeor wall 11 is disposed in a plane generally normal or substantiallyperpendicular to 7 1 a the plane which passes through the rear edges 16of such edge flange or wall 11. The rear edges 16 of the edge wallsection 1E, 2E, 3E and 4E are located in a common plan spaced rearwardlyfrom the tile body it so that the latter is thus tilted or angularlyrelated to such common plane. In the example tile the sections llE and4E of the edge flange or wall 11 which extend between the high corner 1and the diagonally opposite internediate height corners 2 and 4 aredimensionally identical with their maximum widths at the high corner andtheir minimum widths at the intermediate corners. the sections 2E and 3Bwhich extend between the intermediate corners 2 and 4 and the lowcorners 3 of the tile are dimensionally identical and have their maximumwidths at the intermediate corners, being the minimum widths of thesections 1E and 4E, and their minimum widths at the lower corner 3.

One of the conditions which these plastic acoustical tiles mustencounter, after installation into assembled position, is the expansionand contraction of the tiles under the varying degrees of temperature towhich they will be subjected. In the installation of the tiles it isundesirable to leave any appreciable spacing between the adjacent sideedge flanges of adjacent tiles so that in the preferred installationsadjacent side edge flanges are either abutting or very minutely spaced.Particularly under extremes of temperature conditions the expansion andcontraction of the adjacent abutting tiles frequently results inbuckling of the installed tiles with possible breakage or fracture ofportions of adjacent tiles. By my invention I have provided aconstruction and arrangement of the side edge flanges 29 making up theside edge flange or wall structure 11 which reduces the effects ofexpansion and contraction with the tiles in installed position and thussubstantially eliminates the possibility of buckling of and damage tothe tiles. In carrying out this feature of the invention in the exampletile T hereof, I provide relatively wide clearance spaces, separationsor gaps 23 and 23 between the adjacent ends of the flanges 2t) of theside edge flange or wall 11 at each corner of the tile. These spaces orgaps between the edge flanges 2%) at the corners of the tile may extendfor the full width or depth of the flanges at each corner, asillustrated by the space 23 between the adjacent ends of the side edgeflange section 2E and SE at the low corner 3 of the example tile. Or,the spaces may extend from the rear edges 16 of adjacent flanges 2G aportion only of the full width of the flanges as shown by the spaces orgaps 23 between the flanges 24 at the high corner 1 and the intermediateheight corners 2 and 4. Thus the spaces 23 extend from and separate therear edges 16 and the adjacent ends of the flanges at the corners 1, 2and ibut terminate spaced rearwardly from the tile body It with theadjacent ends of adjacent flanges 26 being joined from the inner orforward ends of the spaces 23 to the tile body It). e

In those instances, such as at the corners l, 2 and 4 of the'exampletile T, where the spacing or separation 23 between adjacent ends of theflanges 2t] extends only a portion of the width of the flanges, I mayprovide strengthening and stiffening buttresses 25 which are moldedintegrally with the tile structure and which extend inwardly from thejoined edge portions of the tiles at these corners. Due to the diflerentwidths of the edge flanges at the high and the intermediate heightcorners of the tile, it is preferable to form the buttresses 25 at theintermediate corners 2 and 4 of less length than the length of thebuttresses at the high corner "1, to thus provide the spaces or gaps 23at the high corner 1 and the intermediate corners 2 and 4 ofsubstantially the same lengths as the length of the full width space orgap 23' between the adjacent ends of the flanges 20 at the low corner 3.

It is to be noted that where the tile is provided with spacing or gapsbetween the adjacent ends of the side edge flanges 20 at the corners oftile which are of the full width of the flanges, such as the space orgap 23' at the low corner of the tile T, then the body 10 projectsoutwardly beyond the adjacent ends of the flanges in the form of a sharppointed corner 24. Similarly, where the spacing or gaps 23 extend onlyfor a portion of the width of the adjacent ends of flanges 20, thecorners of the tile will present instead of the sharp pointed corner 24,the sharp edged corners 24'. In either instance these sharply definedcorners formed by what amounts to a cut-back of the adjacent ends of theflanges 20 at the corners of the tile, make possible close, precise andneat fitting of and joints between the corners of adjacent tiles intheir assembled relation in a tile installation, as well as insuringregularity in the resulting positioning of the tiles relative to eachother in the completed installation.

A further feature of the invention which contributes to the limited butfree expansion and contraction of the side edge flanges 20 relative toadjust abutting edge flanges 20 of adjacent tiles in an installation,resides in the formation of the outer side of each flange 20 to provideangularly related surfaces meeting at and forming a ridge 26 disposedlongitudinally along and throughout the length of the flangeintermediate the rear edge 16 thereof and the opposite forward edgealong the tile body 10. In this particular example tile T the ridge 26of each side edge flange 20 is formed by the line of jointure of theoutwardly inclined angular faces 26a and 26b forming the outer sidesurface of a flange 20, although attention is here directed to the factthat if desired or found expedient, the outer side surface of an edgeflange 20 can be formed as a single planar surface with a ridge moldedthereon to extend outwardly therefrom. In this instance the ridges 26 ofthe side edge flanges 20 are each spaced the same dis tance forwardly orinwardly from the rear edges 16 of the flanges and this distance isdetermined from the low corner 3 of the tile T by locating the ridges ina plane which intersects midway of the length of the gap or spacing 23at this low corner. The ridge 26 on the outer side of a flange 20 of atile T will engage with the corresponding ridge 26 on the adjacentflange 20 of an adjacent tile when in assembled relation in aninstallation, so that initially and under the temperature conditions atthe time the tiles are installed the ridges 26 will maintain a veryslight spacing between the tiles which is sufficient to permit expansionof the tiles relative to each other without resulting in damage to ordisplacement of the tiles from their proper installed positions. Witheach side edge flange 20 of a tile being also free to flex or displacelaterally by expansion and contraction due to the gaps between adjaceutends thereof at the corners of the tile, it will be evident that maximumprotection against tile buckling or breakage is provided. The ridges 25may be eliminated so that the adjacent side edge flanges 20 of adjacenttiles are in abutting relationship in an installation of the tile,without seriously impairing the protection against buckling or breakagefrom expansion and contraction, because of the freedom of independentmovement of the edge flanges 20 provided for by the separation of theedge flanges at the corners of the tiles.

A system for interlocking and of assuring proper relative positioning ofthe assembled tiles is provided by the invention and, in the exampletile T hereof, takes the form of alternate pairs of locking lugs 30 andkeeper holes or recesses 31 on the side edge flanges 20. In theparticular arrangement of the locking lugs 30 and recesses 31 providedfor the tile T, each side edge flange 20 has two identical lugs 30spaced apart along one-half of the flange and two identical recesses 31spaced apart along the other half of the edge flange. Each of thelocking lugs 30 is of rectangular cross-section with the long dimensionthereof disposed longitudinally of the edge flange 20 on which mounted,while each of the keeper holes or recesses 31 is also of rectangularplan form and each extends in this instance completely through the edgeflange substantially greater than and approaching twice the length of alocking lug and of a width but slightly greater than and approachingsubstantially the width of a lug.

The locking lugs 36 and'recesses 31 are arranged on the side edgeflanges iii) of the tile T, so that the pairs or sets of lugs 3t}alternate around the tile with the pairs or sets of keeper recesses 31;Thus in the assembly of adjacent tiles the locking lugs 39 of abuttingflanges 2:? or" adjacent tiles will always line up with and be receivedin the recesses 3t.v :In assembling the tiles in an installation thelugs 3b of an edgeflange 26' of the tile being placed in position areinserted into the recesses 31 of the abutting edge flange of theadjacent tile with the lugs of such latter edge flange entering andbeing received in the recesses 31 ot the abutting edge flange of thetilebeing inserted. Where, as is usual, the tile being inserted must beabutted with and against two previously inserted tiles, it will'beobvious that the lengths of the recesses of the abutting tiles make itpossible to position and properly engage a tile being inserted with twopreviously mounted tiles. When in properly installed position the lengthof each lug or positioning pin 36 relative to the length of the recesses31 in which they are received is suchthat with the adjacent side flangesof abutting tiles in alignment, the lugs 5th will be positioned in theirreceiving recesses centrally of such recesses with clearance spacesbetween the ends of each recess and the opposite sides of the lug 343received therein. With the locking lug or pin and recess arrangementproviding the interlocking system of the invention, the assembly of thetiles into an installation thereof is rendered quite simple and theirproper positioning relative to each other and the maintenance of suchproper positioning in the installation after assembly is assured.

The tiles of the invention are designed and intended for bothinstallation by directly adhering them to a mastic coating and bymounting on and suspension from a conventional type of tile suspensionsystem. For mounting from a suspension system mechanically Without theuse of cement, I have provided in each corner of the tile a mountingpost which extends rearwardly from the rear surface 12 of the body ofthe tile. These mounting or suspension posts are identical inconstruction but vary in length in accordance with the corner in whichthey are located. Each post comprises a body 32 which may be ofcylindrical or any other desired shape but which has an axial bore 33therethrough for receiving an attachment member, such as a nail or ascrew by which the tile is secured in position on and suspended from therails of a suspension system, such as any one of the conventionalsystems known in theart, as will be more specifically referred to anddescribed more in detail hereafter. The post 1P at the highcorner lotthe tile has a length such that it projects rearwardly a slight distancebeyond the plane of the rear edges 16 of the flanges 20 of the tile. Theposts 2P and 4P which are located at the intermediate height corners 2and 4 of the tile are of the same length and have their rear endsextending rearwardly the same distance beyond the plane of the edges 160f the edge flanges 2b as the rear end of the post 1P. The post 31 atthe low corner 3 of the tile has a length less than the posts 1P, 2P and4P but such that its rear end projects rearwardly a distance to belocated in the plane of the rear edges of the posts 1P, 2P and 4P. Thusit is assured that when a tile T is mounted in position suspended fromthe rails of a tile suspension system, it will be held substantiallylevel relative to the plane of the rails of the suspension system sothat the tilted face 14 of the tile will be tilted or angularly disposeddiagonally across the tile relative to the plane of the suspension railsfor acoustically functioning in accordance with the principles of theinvention.

The suspension posts 1P, 2P, 3? and 4P may be molded integral withlthetile body it) of a tile T or, as in the examplehereof, they may beprovided with the mounting bases 34 by which they may be solventcemented or otherwise secured on and rigidly to the tile body. Each.

of. the posts is mounted in position with the axial bore 33 therethroughaligned with the sound wave receiving opening 15 which is located in thecorner in which the post is mounted so that this opening 15 provides theentrance into the bore 33 through which the suitable attaching membermay pass position for attachment at its opposite end to the rail of thesuspension system.

As in the usual tile suspension system the rails for practical reasonsare spaced as widely apart asreasonably possible and usuallyconsiderably more than the 12 width of the tiles T of the exampleshereof, I propose to secure two tiles together in a desired relativepositioning of the respective high corners 1 thereof so that thesecombined tiles will then bridge and may be mounted on and suspended fromrails of a suspension system spaced approximately 24" apart. Theconnection of the tiles into a rigid assembly may be made by placingconnecting plate members joined to the adjacent ends of aligned sideedge flanges of the joined tiles with these connecting plates beinglocated in and extending through the spaces or gaps 23 at the adjacentcorners of the joined tiles. This connecting arrangement is shown inFig. 16 of the drawings. I

An example of the suspension mounting of acoustic tiles of the inventionto one of the standard types of suspension systems is illustrated inFigs. 14 and 15 of the accompanying drawings. The selected suspensionsystem includes the rails R transversely across the undersides of whichthe nailing channels 46 are suitably attached in spaced, parallelrelation. The channels 49 are spaced approximately 24" apart and may bebridged by two (2) of the tiles ot' the example form of the invention.The tiles U are connected together in substantially fixed, rigidrelationship by a connecting plate 41 fixed, as by solvent cementing, tothe adjacent inner sides of the tile flanges 20 at the adjacentcorners'of abutting tiles, as will be clear by reference to Fig. 16 ofthe drawings in particular. It is to be noted that connecting plates 41are provided at opposite sides of the joined tiles and that eachconnecting plate 41 extends through and is received in the adjacent andaligned separations or openings, such as the openings 23, between theedge flanges at the adjacent ends of the abutting tiles. The two tilesso joined are then placed in position across and bridging adjacentchannels 40 with the suspension posts of the tiles along opposite sidesthereof engaged against and aligned with the channels, after whichattaching members such as the nails 42 are driven upwardly through thebores 33 in the posts into clinched engagement in the channels as shownin Fig. 15.

*A tile T of the design and construction hereinbefore described may beeifectively used as an acoustic unit Without the sound wave absorbingpad or mat P but to increase the acoustical efliciency of the tile whenso used or when used with a pad P, I have provided, in accordance withthe disclosures and principles thereof of my above referred toU.S.patent applications Serial Nos. 283,707 and 379,918, a plurality ofdamping tubes 35 which project rearwardly from the rear surface 12 ofthe tile body 10 at and in axial alignment with the sound wave receivingholes or apertures 15, respectively, through the tile body 10. In'thisinstance these tubes 35 are molded integral with the tile body 10 andhave relatively short lengths to project but relatively short distancesrearwardly from the rear surface 12 of the body 10.

If a tile T for suspension from a tile mounting and suspension system isto be used with a sound absorbing pad or mat P, such mat, ashereinbefore referred to, is of dimensions to substantially till thespace enclosed by the side edge flanges 2i? and to completely cover therear surface 12 of the tile body 1'8 and the tubes 35 projectingrearwardly therefrom. The corners of the pad may be suitably cut out orcut away, as indicated at 36 for clearance for the tile suspension posts1P, 2P, 3? and 4P in the corners of the tile, as will be clear byreference to Fig. 10. One of the features of the invention whichcontributes to the acoustical efliciency of the tile when used with amat or pad P, is the provision of such pad of varying thicknessesthroughout its area so that the forward side of the pad is against andcovering the rear surface 12 of the tile body it while the rear side ofthe pad is located throughout its area substantially in the plane inwhich the rear edges 16 of the side edge flanges 20 of the tile arelocated. With such a pad P of varying thicknesses I have found that thepad Will more efficiently absorb and dampen sound waves over a widerrange of frequencies than will a pad of substantially equal thicknessthroughout its area. This sound wave absorbing pad P of varyingthicknesses with the damping tubes 35 discharging directly thereagainstand thereinto at the forward side thereof, together with the tiltedsound wave receiving face of the tile, gives an acoustical tile of highefficiency, yet of simple and inexpensive design and construotion.

Provision is made with certain forms of the tile T for mounting thereofdirectly onto a mastic or cement coating with the tile then adheringthereto in its installed position. This is carried out broadly inaccordance with the cement mounted acoustical tile disclosures of mypending US. patent application Serial No. 379,918, in which discs areprovided on the tile body in locations spaced from the rear side thereofparallel therewith and leaving the rear surfaces located in the plane ofthe rear edges of the side edge flanges of the tile. Thus the rearsurfaces of such mounting discs may receive thereon .the mastic foradhering the tile directly to the surface on and over which the tile isto be mounted and installed. In the present example tile unit U I haveprovided such pad retaining and cement discs C of improved constructionand mounting. Referring now to Figs. 10, 11 and 12 in particular, eachsuch disc C happens to be of circular form and is comprised of the platebody 50 of relatively thin plastic material providing the outer planarside surface 59 and the planar under surface 51 adapted to engageagainst the outer side of a sound absorbing pad or mat P when inassembled position in the acoustical tile unit. In order to increase thecement or mastic holding efficiency of a disc C the body 50 thereof isreticulated over the major area thereof by providing the multiplicity ofclosely spaced openings 52 therethrough which in this instance are shownof rectangular form.

Each disc unit C is provided with a plurality of supporting posts 53 bywhich the unit is mounted and attached in assembled position on a tileT. In this particular example each disc unit C is provided with twelve(12) of such mounting posts 53 extending rearwardly from the rear side51 of the disc body 50 with the posts parallel and spaced apart in asymmetrical arrangement thereon. These posts 53 are in the presentexample formed of plastic and molded as integral components of the discunit C. Each of the posts 53 may be of tubular form as here shownprovided with a closing wall 54 inset axially from the outer end of thepost, although if desired, such wall 54 may be eliminated, as will beexplained hereinafter. Four (4) of the posts 53 are positioned on a discbody 50 spaced apart equal distances around the center of the disc bodyat locations intermediate such center and the outer or peripheral edgeof the disc body, while the remaining eight (8) of the posts 53 aremounted in pairs spaced equal distances apart around the peripheralportion of the disc body in locations adjacent but spaced slightdistances inwardly from the peripheral or outer edge of the body, aswill be clear by reference to Figs. 11 and 12. In order that the discunits C will be interchangeable between the locations at which mountedon the inclined or tilted body it) of a tile T,the posts 53 are allformed of the same length. Thus the production cost and assemblydifficulties encountered with providing a specialdisc for each locationon a tile body are eliminated.

With a tile unit U of this particular example four (4) cement receivingdisc units C are provided mounted spaced equidistant apart on and spacedfrom the rear side 12 of the tile body it with each unit C substantiallycentered on a quarter section of the area of the tile rear surface, asshown in Fig. 10. The disc units C are mounted with their rear or outer,cement receiving surfaces 59 located in a common plane located in andparallel with the common plane in which the rear edges 16 of the edgeflanges fill of the tile T are located. The body it) of a tile T isprovided on the rear side 12 thereof at each location of a disc unit Cwith the mounting pedestals 55 molded integrally therewith and spacedapart thereon in a spacing pattern and arrangement for axial alignmentthereof With the mounting posts 53, respectively, for the disc unit C tobe mounted thereon and attached thereto. The mounting pedestals 55 ineach quarter section location for a disc unit C on the rear side of thetile present seating surfaces 56 thereon and therearound spacedoutwardly distances from the rear surface 12 of the tile body T inaccordance with the depth or Width of the tile flanges 3.1 at theadjacent corner of the tile. In other words, the group of disc unitmounting pedestals 55 adjacent the high corner 1 of the tile will belocated in a common plane spaced outwardly a greater distance from therear surface of the tile body 12 than the seating surfaces on the groupsof mounting posts 55 at the intermediate height corners 2 and 4 and thelow corner 3 of the tile body. With the mouting posts 53 of the discunit C being all of the same length, the seating surfaces 56 on thegroups of pedestals 55 will be located spaced the necessary distancesoutwardly from the rear surface 12 of the tile body 10 to insurepositioning the cement receiving surfaces 59 of the disc unit C in thecommon plane of the rear edges 16 of the tile flanges 11. in thisspecific example each pedestal 55 includes a reduced diameter mountingpin portion 57 which extends coaxially outwardly from its pedestal 55and which has an external diameter to be received in the open end boresof the tubular posts 53 of a mounting disc below the closing walls 54 ofsuch posts. The mounting of the posts 53 of a disc unit C on thepedestals 55 will be clear by reference to Fig. 11 of the drawings, inwhich it will be noted that the outer edges of the tubular posts 53 seatupon the seating surfaces 56 of the pedestals 55 respectively alignedtherewith, so that proper spacing of such surfaces 55 from the rearsurface 12 of a tile T will insure proper location of the rear surface30 of a disc unit mounted thereon. Preferably the disc mounting posts 53are attached in fixed positions on and to their pedestals 55 by solventcementing.

An acoustical tile unit U embodying the assembly of a tile T, a soundwave absorbing mat or pad P of varying thicknesses thereacross and thepad retaining and mastic receiving disc unit C is shown in Fig. 10 inconnection with Fig. 11. It will be noted that the bodies 51} of thedisc unit C are positioned over and against the rear side surface of thepad P and thus retain this pad in assembled relation in the tile T as apermanent component of the resulting self-contained acoustical tile unitU. The rear surfaces 59 of the disc bodies are located in a common planewhich is preferably also the common plane of the rear edges 16 of thetile flanges 11, and may thus receive thereon portions of mastic whichmay be spread thereover and which will key into the openings 52 of thedisc bodies 50. With the mastic on the discs C a tile may be directlyapplied and pressed onto the surface on which it is to be installed withthe mastic then setting and fixing the tile in its installed position.

The primary purpose of the closing walls 54 in the mounting posts 53 isto prevent seepage or bleeding of mastic from the rear surface 59 of adisc body 50 to the face 14 of the tile. It will be noted that in theillustrated examples each post 53 isformed with its bore in axialalignment with an opening -15'through the face 14 of the tile so thatmeans to prevent such condition is preferably provided, which meanswhile shown as the closing walls 54 may take other forms for closing-dany communication between the cement receiving surface 59 of a disc unitC and the face 14 of a tile.

In a tile unit U the mat or pad P is provided with the necessary holesor openings 60 cut or otherwise formed therethrough for receiving thepedestals 55 and disc posts 53 attached thereto in the assembledpositions thereof as shown in Fig. 11. i

In Figs. 1, 2 and 3 of the drawings I have generally schematicallyillustrated three (3) possible installations of acoustical tires or tileunits U having the inclined or tilted faces in accordance with mypresent invention. In

Fig. 1, for example, the tile units U are arranged in the; rows fromleft to right with their high corners 1 alter- .nating but with thealternating high corners of one of the adjacent rows abutting the highcorners of the first-mentioned row. In Fig.' 2 a row of the tiles fromleft to right is arranged with the high corners alternating but with thelow corners'of adjacent rows located abutting or at the alternating highcorners of the first-mentioned row. In Fig. 3 an assembly is exemplifiedin which the high corners of the tiles of adjacent rows are locatedabutting so that series of four (4) tiles make up the pattern of thisinstallation in which all of the high corners are joined together andabutting. The foregoing examples are purely illustrations of possiblerelative arrangements of these tilt or inclined face tiles to givedifferent and pleasing visual effects While, retaining the substantiallyincreased acoustical eificiency of thetile units as hereinbeforeexplained,

It Will also be evident that various changes, modifications, variations,eliminations, substitutions andadditions may be resorted to in thacoustic tiles or acoustic tile units per se and in the installationsthereof, whether of the suspension or the direct mastic attached type,without departing from the broad spirit and scope of my presentinvention and the several features thereof; hence it is not intended ordesired to limit the invention in all respects to the exact and specificillustrative examples thereof herein presented and described, except asmay be required by specific intended limitations thereto in any of theclaims hereto appended.

What I claim is: I t 1. An acoustic tile comprising, in combination, atile body of generally rectangular plate form having a front side, arear side, and outer edges therearound joining at and forming thecorners of said tile body; said front side of said tile body providing agenerally planar face surface thereover; edge flanges extendingrearwardly from and around the outer edges of said tile body surroundingand enclosing said rear side thereof between said corners of said tilebody; said edge flanges having rear edges located in a substantiallycommon plane spaced rearwardly from said tile body; said tile body andsaid planar front face surface thereon being tilted bodily andpositioned on and relative to said edge; flanges inclined diagonally andrearwardly thereacross from one corner of said tile body to thediagonally opposite corner thereof; and said tilted and diagonallyrearwardly inclined tile body together with said edge flangestherearound forming thereetween a rearwardly open space at and over therear side of said tile body of decreasing depths thereacross' in thedirection from said first mentioned corner to said 14, second mentioned,diagonally opposite cornerof said tile body. 7

2. An acoustic tile. comprising, in-combination, a tile body ofrelatively thin plate-form of generally rectangular plan shape having afront side providing a generally planar face surface thereover, anopposite rear side, and outer edgesitherearound joining at and formingthe corners of said tile body; edge flanges extending rearwardly fromand around said outer edges ofsaid tile body be P tween said cornersthereof terminating in rear edges located in a substantiallycommonplane; said edge flanges being of maximum depth'rearwardly at one cornerof said tile body and of minimum depth rearwardly at the corner of saidtilebody diagonally opposite thereof of maximum depth; said edge flangesprogressively' decreasing in depth around the opposite outer edges ofsaid tile body from said corner of said tile body at which said edgeflanges are of maximum depth to said diagonally'opposite corner of saidtile body at which said edgefianges are of minimum depth; said tile bodybeing located on and relative to said side edge flanges in positiontilted bodily rearwardly with said planar front face surface thereoflocated in a plane inclined diagonally rearwardly from said corner ofsaid tile body at which said edge flanges are; of maximum depth to saiddiagonally opposite corner of said tile body at which said edge flangesare of minimum depth.

3. An acoustic tile comprising, in combination, a tile body of plateform of generally rectangular plan shape having a front side providing agenerally planar face surface thereover, an opposite rear side, andouter edges therearound joining at and defining the corners of said tilebody; edge flanges extending rearwardly from and around said outer edgesof said tile body between said corners thereof; said edge flangesterminating in rear edges located in a substantially common plane spacedrearwardly from said tile body; said edge flanges being of maximum depthrearwardly at one corner of said tile body and of minimum depthrearwardly at the corner of said tile body diagonally opposite saidcorner of maximum depth thereof; said edge flanges having the forwardedges thereof at and around said outer edges of said tile body locatedin a common plane tilted and inclined at an angle to said common planeof said rear edges thereof in a direction rearwardly front said cornerof said tile body at which said edge flanges are of maximum depth tosaid corner of said tile body at which said edge edge flanges in a'plane parallel with the plane of the said forward edges with saidplanar face surface of the front side of said tile body thereby tiltedand inclined rearwardly in a plane substantially parallel with theinclined common plane of said forward edges of said edge flanges.

4. An acoustic tile comprising, in combination, a tile body of plateform having a front side, a rear side, and outer edges therearoundjoining at and forming the corhere of said tile body; said front side ofsaid tile body providing a generally planar face surface thereover andthereacross; said tile body having edge flanges extending rearwardlytherefrom around said outer edges thereof between said corners ofsaidtile body; said rearwardly extending edge flanges surrounding andenclosing the rear side of said tile body and having rear edges locatedin a substantially common plane spaced rearwardly from said tile body;said tile body being positioned on and relative to said edge flangesinclined rearwardly at an angle diagonally thereacross from one cornerof said tile body to the diagonally opposite corner thereof with saidgenerally planar face surface of said front side of said tile bodylocatedrthereby in a plane tilted and inclined rearwardly at an angle tosaid common plane of said 15 tween at the rear side of said tile body arearwardly open space progressively decreasing in depth across the rearside of said tile body in the direction of inclination rearwardly ofsaid tile body.

5. An acoustic tile comprising, in combination, a tile body of generallyrectangular plate form having a front side, an opposite rear side, andouter edges therearound joining at and forming the corners of said tilebody; said front side having thereover a generally planar face surface;edge flanges extending rearwardly from and around said outer edges ofsaid tile body between said rers thereof; said edge flanges having rearedges located In a common plane; said edge flanges having their maximumdepth rearwardly at one corner of said tile body and having theirminimum depth rearwardly at the corner of said tile body diagonallyopposite said corner thereof at which said flanges have their maximumdepth; said edge flanges progressively decreasing in depth rearwardlyaround said tile body from said corner thereof at which said edgeflanges are of maximum depth to said diagonally opposite corner of saidtile body at which said edge flanges have their minimum depth; said tilebody being tilted bodily rearwardly across said edge flanges from saidcorner of said tile body at which said edge flanges are of maximum depthto said diagonally opposite corner of said tile body at which said edgeflanges are of minimum depth with said generally planar face surface ofsaid front side of said tile body being thereby located in a planeinclined at an angle rearwardly to the common plane of said rear edgesof said edge flanges; and said rearwardly inclined tile body togetherwith said edge flanges therearound forming therebetween a rearwardlyopen space decreasing progressively in depth diagonally across the rearside of said tile body in the direction of rearward tilt of said body.

6. In the combination of claim said tile body being provided with amultiplicity of relatively small diameter sound wave receiving aperturestherethrough opening through said face surface on said front side ofsaid tile body into said space at the rear side thereof; and saidmultiplicity of sound wave receiving apertures being located in closelyspaced relation over substantially the entire area of said face surface.

7. In the combination of claim 5, a sound wave absorbing material mat ofdecreasing thicknesses diagonally thereacross mounted in andsubstantially completely occupying said enclosed space between said sideedge flanges and between said rear side of said tile body and saidcommon plane of said rear edges of said edge flanges.

8. in the combination of claim 5, said tile body being provided with amultiplicity of sound wave receiving apertures therethrough closelyspaced apart over substantially the entire area of and opening throughthe face surface thereof at the front side of said tile body; sound wavedamping tube members projecting rearwardly from said rear side of saidtile body in communication with and an axial continuation of saidapertures, respectively; a sound Wave absorbing material mat mounted inand substantially completely occupying said enclosed space of varyingdepths between said edge flanges and between said rear side of said tilebody and said common plane of said rear edges of said edge flanges withsaid sound-absorbing material mat having varying thicknessescorresponding, respectively, to said varying depths of said space; saidtube members being engaged at their rear ends with and having sound wavedischarge openings therefrom to said variable thickness sound waveabsorbing material mat; and means securing said sound wave absorbing matto and in position in said space over the rear side of said tile body.

9. An acoustic tile comprising, in combination, a tile body of generallyrectangular plate forrnhaving a front side providing a generally planarface surface thereover, an opposite rear side, and outer edgestherearound joining at and forming the corners of said tile body; outeredge flanges extending rearwardly from said outer edges of said tilebody around and between said corners thereof; said outer edge flangessurrounding and forming an enclosed space over said rear side of saidtile body; said outer edge flanges having the rear edges thereof locatedin a common plane and meeting to form outer edge flange corners at saidcorners, respectively, of said tile body; said tile body being tiltedbodily rearwardly and diagonally across and between said outer edgeflanges from one corner thereof to the diagonally opposite corner ofsaid outer edge flanges; and said outer edge flanges of said tile bodyprogressively decreasing in depth rearwardly therearound from said firstmentioned corner to said diagonally opposite corner with said planarface surface of said tile body thereby inclined rearwardly across saidtile from said first mentioned corner to said diagonally oppositecorner.

10. An all-plastic acoustic tile comprising, in combination, arelatively thin tile body of plastic material of generally rectangularplate form having outer side edges therearound joining at and formingthe corners of said tile body; plastic material edge flanges integralwith said tile body extending rearwardly from and along said outer sideedges, respectively, of said tile body between said corners thereof;said outer side edge flanges terminating in rear edges located in acommon plane spaced rear- Wardly from said tile body; said edge flangeshaving maximum depth at one corner of said tile body and minimium depthat the diagonally opposite corner thereof and progressively decreasingin depth around said tile body from said corner of maximum depth to saidcorner of minimum depth; said tile body being located on and relative tosaid side edge flanges in position inclined rearwardly diagonallythereacross and therebetween from said corner of maximum depth to saiddiagonally opposite corner of minimum depth of said edge flanges; theadjacent ends of said edge flanges at said corner of said tile body atwhich said edge flanges are of minimum depth being separated and spacedapart for the full depth thereof; and the adjacent ends of adjacent edgeflanges at said other corners of said tile body being spaced apartinwardly from and through their rear edges distances substantially equalto the length of said separation of said adjacent edge flange ends atsaid corner of said tile body at which said edge flanges are of minimumdepth.

11. An all-plastic acoustic tile comprising, in combination, a tile bodyof plastic material of generally rectangular plate form having a frontside providing a face area thereover, a rear side, and outer edgestherearound joining at and forming the corners of said tile body; saidtile body having edge flanges extending rearwardy from and around saidouter edges of said tile body integral therewith between said corners ofthe latter; said edge flanges terminating in rear edges located in acommon plane; said tile body being inclined rearwardy across andrelative to said edge flanges in a plane at an angle to said commonplane of said rear edges of said edge flanges; spaced sets of spacedsupporting posts mounted in fixed positions spaced apart on andextending rearwardly from said rear side of said tile body; mountingdiscs each providing with supporting legs therefor extending laterallyfrom one side thereof mounted on and attached to a set of said spacedsupporting posts, respectively, positioning said mounting disc on saidtile body; said legs of said discs being all of equal lentghs; and saidposts of each of said sets of spaced supporting posts being of differentlengths from the lengths of said posts of said other sets and projectingdistances rearwardly from said rear side of said tile body positioningsaid mounting discs in attached positions thereon with said rearsurfaces thereof substantially in said common plane of said rear edgesof said edge flanges.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS Rcyam et al Aug. 12, 1913 Mazer Feb. 22,1916 Norris Aug. 27, 1929 Kellogg et a1 Sept. 12, 1933 MacDonell Oct.10, 1933 Maze-r June 5, 19341 Denk July 10, 1934 Find: July 24, 1934Hoff et a1. Oct. 30, 1934 Slidell Feb. 26, 1935 Newport et a1. Feb. 3,1942 Pauli July 6, 1943 Jacobson July 20, 1943 T rippensee Feb. 27, 1945Hurley -2 Dec. 31, 1946 Mazer Sept. 15,. 1953 Maccaferri July 24, 1956Engsl Nov. 20, 1956 FOREIGN PATENTS France, Apr. 14, 1947

